1. Field of the Invention
The invention relates to a therapeutic apparatus for the support of patients having difficulty in sputum expectoration when afflicted with a respiratory disease such as chronic bronchitis, bronchiolitis, bronchial asthma, bronchiectasis, pulmonary tuberculosis, and pulmonary emphysema. More particularly, the invention relates to a therapeutic apparatus using an interference low frequency wave, which enables sputum in the trachea and a bronchial tube of the chest to be easily expectorated by supplying an electrical stimulation.
2. Description of the Related Arts
Recently, due to the increase in the population and an increase in the number of aged people, and further, changes in environmental conditions, for example, air pollution, the number of people suffering from chronic respiratory diseases such as chronic bronchitis, bronchial asthma and pulmonary emphysema has increased.
Among the symptoms, such as sputum accumulation, coughing, and difficulty in breathing which are accompanied by such respiratory diseases, the difficulty of expectoration of sputum appears most frequently in medical records and has becomes one of the main symptoms particularly in the pneumonopathy of a chronic obstruction, for example, chronic bronchitis, bronchial asthma and pulmonary emphysema as well as the labored respiration.
In the medical treatment of respiratory diseases, it is very important to cause the expectoration of sputum, which is a major cause of labored respiration and of infections of, for example, a respiration tract, and such expectoration is effected by a drug treatment and physiotherapy.
Known pharmaceutical compounds for effecting expectoration in a drug treatment are, for example, iodic salt, benzylamine, ferment compound, cysteine compound, and "ALEVAIRE".
All of these compounds for enabling expectoration directly or indirectly affect a rheological characteristic such as an adhesive power, a spinnability or a phenomena of thixotropy of a sputum. However, inevitably side-effects occur depending upon the usage of such compounds, and therefore often such a treatment will have an adverse effect on the human body. Also, in many experimental medical treatments, a sufficient expectoration was not obtained when these compounds were used.
In this connection, physiotherapy by a postural drainage method is well known.
In this method, the patient's whole body or the chest portion must be inclined to enable sputum to be expectorated under the force of gravity, and in addition, a method of tapping the chest or applying external vibration to the chest is used to enable the sputum to be easily expectorated.
Nevertheless, although there is less fear of side-effects from the drug treatment, it has a defect in that the expectoration of sputum is not altogether satisfactory.
In another method for stimulating expectoration, as one kind of physiotherapy a pressure wave having a frequency of less than 10 Hz is directly supplied into the trachea and a respiratory tract by way of the trans-tracheal, but this method requires many improvements.
As a new treatment for effecting expectoration in physiotherapy, a treatment using a therapeutic apparatus for improving a respiratory function and/or symptoms thereof by utilizing a low frequency wave is disclosed in, for example, Japanese Unexamined Patent Publication 60-31766, but the effecting of expectoration by electric stimulation with a interference low frequency wave varies greatly, depending upon the conditions under which the electric stimulation is carried out and the position at which the therapy is applied.
Therefore, much research has been made into the conditions needed to obtain the best effects from this kind of treatment.